In U.S. Pat. No. 3,305,991 in the name of the present inventor, there is described a reinforced modular foam panel which consists of a three-dimensional lattice or matrix framework formed from steel wires welded together, with the interior volume of the lattice being filled with a hard-setting foam plastic material which surrounds and bonds to the internal braces of the lattice. As further described in U.S. Pat. No. 3,838,241, also in the name of the present inventor, there is described apparatus for manufacturing the wire framework. The present invention is directed to an improvement in both the construction of the wire framework for the panel and the apparatus for manufacturing the wire framework.
As described in the above patents, the framework is constructed by forming a plurality of wire trusses which are then arranged in parallel and joined by transverse wire runners to form a three-dimensional wire matrix. Each truss consists of parallel spaced runners joined by a plurality of spaced struts which extend diagonally between the spaced runners. The diagonal struts extend alternately in opposing directions so as to form a zigzag pattern along the length of the truss. In addition, closeout struts at the end of each truss section are provided which extend perpendicular to the two runners. While this construction results in a rigid highly satisfactory wire framework, this design has required that the trusses be individually constructed. Since each panel utilizes a large number of parallel trusses, a large number of truss-making machines is necessary to keep up with a single matrix framework fabricating apparatus on a continuous basis.